Saw-plate and inserted saw-tooth



` (No Model.)

J. J. BOWEN. A

r SAW PLATE AND INSERTED SAW TOOTH. No'. @$3,197. A Patented Aug. 14,1883.'

Wkfwsses I 'Mwewm UNITED STATES` JOHN J. BOWEN, on sAN PATENT OFFICE.

FRANCISCO, CALIFORNIA.

SAW-PLATE ,ZAND msi-:RTED SAW-TOOTH.

' SPECIFICATION forming part of Letters-Patent No. 283,197, dated August14, 1883.

,Application tied December es, 1ste. (No model.)

To Illu/hom, t may concern: i

\ Beit known that I, JOHN J. BOWEN, of the city and county ofSan`Francisco, State of California, have invented Vcertain new anduseful Improvements in Saw-Plates and Inserted Saw-Teeth; and I dohereby declare that the following is a full, clear, and exactdescription thereof. A

My invention relates more particularly to that class of saw-plates andinserted saw-teeth in which a crescent-shaped tooth is turned into a`circular recess in the edge of the sawplate, so that one end will formthe cuttingpoint. Latterly these teeth have been-improved bycutting offthe cutting end of the crescent-,shaped plate and inserting a'removablecutting point or bit in place of the portion removed in such manner thatthe crescentshaped .piece serves as a holder for the bit.` My inventionis app'licable, however, to any form of inserted teeth, but is niostbeneficial where narrow bits are used.

It consists in cutting "an irregular-shaped piece out of the saw-platejust back of the cutting point or bit and inserting inthe recess` thusformed a patch-plateV the back edge ofwhich fits theirregularities-ofthe recess, while itsfront edge conforms to the shapeof the recess in which the saw tooth or bit is secured. The object andfunctionsof this inserted patch will be hereinafter described.

`I Eteferring to the 4accompanying drawings, Figurel shows the concavetooth-socket and patch ready tobe inserted. Fig. 2 shows a section of asaw-platehaving two teeth complete and one incomplete. j A

Let A represent the saw-plate. The edge of this saw-plate is providedwith recesses atl regular intervals apart,'in which the inserted teethare fitted.

B is the crescent-shaped tooth-holder, `which is inserted in the recessin the saw-plate by being turned into the recess, and is heldin place bya V- shaped dovetail in the usual way.`

C is the inserted bit or removable cuttingpoint. Just back of thecutting-point C, I cut out of the saw-plate an irregular-shaped piece,

so as to form an opening or recess, which eX- tends down into the plateas far as or below the point where the bit C extends, and in the recessthus formed I t a patch, D, the back edgefof which the irregular shapeof the edge of the recess, while its front edge conforms to the shape pof the'recess in which thetooth or the toothholder' and bit are secured.The irregular shape of theback edge of the patch-plate fitting in thecorresponding edge of the recess enables me to lock the patch in placeby means of a rivet or key-pin, fi, which passes through a hole made onthe line of juncture at Vthe lower edge of the patch. It is thereforeimmaterial what particular irregular shape the patch iitsagainst; but Iprefer an S shape, as more convenient to make, and because it has noangles or sharp corners. The back edge of the patch is dovetailed-intothe back edge ofthe recess in the usual way. This arrangement holds thetooth or bit with an elastic grip, which prevents it from beingdisplaced. The special'oflice of thepatch, however, is to permit of thatportion being renewed when it becomes worn or broken. |Ihe sawdust,passing back from the throat of the tooth, soon wears' the sides of thesaw-plate thin at this point; but by inserting the patch-piece itreceives the wear, and `can be renewed when desired, thus preserving theplate. The frequent removal and replacement of the saw tooth or bit alsowears the edge of the recess, so that the tooth or bit becomes loose, inwhich condition it is liable to come out. This diiii- `culty is alsoremedied by the patch-plate, as a new one can beinserted at any time,thus keeping the teeth tight.

VIn case a tooth or bit should strike against a hard substance whenpassing through a log,

instead of breaking the plate, as heretofore,

- the patch-piece only will Vbe broken, and the saw can be repaired byinserting a new patch.

Having thus described my invention, what I claim, and desire to secureby Letters Patent,

1s n i The saw-plate A, having a recess formed in it directly behind thecutting point or bit, the back edge of which is irregular inshape, incombination with a patch, D, the back edge of which corresponds with andiits the back edge of the recess, while its front edge conforms with thecurve of the recess in which the saw-tooth fits, the tooth-holder B, andthe re- IOO movable cutting-point C, substantially as speci- In witnesswhereof I have hereunto set my hand and seal.

p JOHN J. BOWEN. [Ls] W'itnesses:

JOHN D. GAGNON, AMBROsE M. WILLIS.

